Tube-joint for sectional boilers



(No Model.)

.Nl W PRATT. TUBE-JOINT POREEGTIONAL BOILERS.

' I Y Y '34LW1 Lm @QMMMQW 727 7% MW w/ww UNITED STATES PATENT OFFICE.

NAT. W. PRATT, OF BROOKLYN, NEW YORK.

TUBE-JOINT FOR SECTIONAL BOILERS.

srncrrrcnrrrolv forming part of Letters Patent No. 527,883, datedOctober 23, 1894. Application filed March 28, 1891. Renewed February 24,1894. Serial No. 501,374. (No model.)

i such tubes to their seats have heretofore been proposed; and one ofthe means heretofore employed, as set forth in Letters Patent No.265,234, dated October 3, 1882, consisted in taperingone end of the tubeto fit a tapered opening in a tube header, while the opposite end of thetube was straight, but slightly reduced in diameter to fit an opening inthe opposite header, which was also of taper form but larger than thegreatest diameter of the tube to permit its withdrawal therethrough, thejoint between the reduced end of the tube and its tapered seat beingformed by a rigid annulus straight upon its inside to fit the tube endand tapered on its exterior to fit the tube seat opening and drivenforcibly to such seat, to secure the tube therein and make a tight jointtherebetween.

The presentinvention contemplates the use of tubes whether of wrought orcast iron as they are ordinarily found in the market, and their use astubes, fiues, or other conduits, without any previous shaping orpreparation and in connection therewith asplit or divided annulus shapedon its inner side to fit the exterior of the tube and tapered on itsexterior to fit a tapered opening in the tube sheet, header or otherseat, whereby such annulus, capable of yielding diametrically, isadapted to conform to the inequalities of such ordinary tube and willthereby aid in insuring a tight joint. The annulus of soft metal andwhether split or not, is formed on its large or outer end with aprojecting neck immediately adjacent its inner surface to provide anannular body of metal adapted to be calked or upset into forciblecontact with the surface of the tube and thereby tighten the jointbetween the annulus and the tube; and this neck may be formed from theedge of both surfaces of the annulus by making a groove in its outer endwhereby the metal of the projecting necks may be forced by the calkingtool in opposite directions-against the walls of the tube seat openingand against the surface of the tube.

As a better understanding of the invention will be had by a detaileddescription thereof, such description will now be given, reference beingmade to the accompanying drawings, in which Figure l is a sectionalelevation of so much of a tube and its connection with its front andrear seats as is necessary to an understanding of the invention. Fig. 2,is an enlarged sectional elevation of one end of the tube and its seat.Fig. 3, is a perspective view of the annulus. Figs. 4 and 5 aresectional views of modified forms of the annulus and the tube seat.

It is to be understood that so far as the particular means now to bedescribed of securing the tubes to their seats is concerned, the tube ortubes may be employed as water tubes in sectional steam boilers as forinstance of the well known Babcock d5 Wilcox type; as flues, as inordinary boilers; as steam, water or air tubes in steam, hot water orair radiators; as tubes in refrigerating apparatus, and in fact in allsituations, apparatus or devices in which tubes held in seats areemployed, the particular connections of the tube shown being simplytaken as illustrative of one of the many examples of its use.

The tube a, in said drawings, is a tube of suitable diameter and length,of wrought or cast iron and preferably taken as ordinarily found in themarket without any fitting or dressing for use in connection with theim.- proved means of connecting it to its seat or seats. The tube seats12, are shown as provided at one end in a plate of sheet metal 0, and atthe opposite end in a header d, of the form usually found in the Babcock85 Wilcox type of generators. Each tube seat is formed by a taperedopening in the metal, header or the like, two openings when consideredtogether being tapered from opposite directions, the larger diameter ofeach opening being outward to facilitate the insertion, drivinghome, andcalking of the securing annulus e.

The securing annulus in its preferred form is split or divided as shownin Fig. 3, having an interior diameter and straight surface The annulusafter being placed around the tube in position to enter or alreadyentered in the seat opening is forcibly driven home by any suitable toolas for instance the annularly formed tool f, indicated by dotted linesin Fig. 2. In this operation the flexibility of the securing annulus, byreason of its being split, will allow the walls of the taperedseat'opening to crowd the annulus around the tube in forcible andbinding contact with its surface so that the joint between the two andwith the seat opening will be absolutely tight. This operation alsocauses the opening of the split in the annulus to-be also closed uptightly. The friction between the annulus, the tube, and the walls ofthe seat opening will be great enough to hold the annulus firmly inplace, and in the example of the tube connection with the header d, inFig. 1, the pressure in the header will materially aid in holding theannulus in position.

As an additional security against any leakage past the joint formed bythe securing annulus, its larger end is formed with a con tinuous groove2, which provides on the end of the annulus an inner and an outerannular neck of metal 8, 4, the former lying against the surface of thetube and the latter against the wall of the seat opening. Each of theseannular necks of metal is calked by a proper calking tool against thetube and wall of the seat opening respectively, thereby completelyclosing all openings between the annulus and the tube which may haveremained by reason of the irregular surface of the tube after drivingthe annulus home in the first operation; and also between the annulusand the wall of the seat opening.

Instead of providing both of the annular necks of metal 3, 4, on the endof the annulus one of them may be omitted as for instance the neck 4, asshown in Fig. 4, wherein the neck 3, may be similarly calked overagainst the surface of the tube.

The wall of the seat opening may be plain tapered as shown or as in Fig.5, it may have an annular groove 5 formed in it into which the annularneck 4. may be calked as is shown partially in Fig. 5, whereby the neckand groove form a key securely locking the annulus in place.

From the foregoing it will be seen that an exceedingly simple mode ofconnecting the tube to its seat is provided, permitting the use ofwrought or cast iron tubes as they are ordinarily found in the marketwithout the necessity of shaping, dressing or fitting their ends foruse; and by employing a split annulus as distinguished from a rigid one,the operation of driving it home effectually closes the annulus aroundthe tube; and by the final operation of calking the closing of allopenings in the connection is insured anda tight joint formed.

I am aware that tube joints have been made wherein a solid taperedannulus has been employed encircling the tube and bearing upon the tubesheet, and also wherein a divided annulus has been inserted within thetube and expanded by permanent internal devices to press and hold thetube in contact with the sheet and I do not claim such expedients.

What is claimed is 1. As a means of securing a tube in its seat, adivided ring or collar of ductile material having its inner bearingsurface conformed to the tube and its outer surface to a tapered seat inthe sheet, plate, or header to which the tube is secured.

2. The herein described tube connection, consisting of a tube seattherefor of tapered form and having an annular groove therein,

and a soft metal annulus adapted to the tube and its seat and having aprojection for calking the annulus in place and adapted to interlockwith said annular groove.

In testimony whereof I have hereunto set my hand, this 18th day ofMarch, A. D. 1891, in the presence of two Witnesses.

NAT. W. PRATT.

Witnesses:

FRANK L. WARD, L. D. BURNHAM.

